ABSTRACT
BACKGROUND: Conventional therapy for canine acral lick dermatitis (ALD) consists of systemic antibiotics and anti-anxiety medications. Low-level laser therapy (LLLT) is a noninvasive therapy used to treat inflammatory and painful conditions. HYPOTHESIS/OBJECTIVES: The primary objective was to determine whether LLLT with conventional therapy would be beneficial as an adjunct treatment for ALD. We hypothesized that LLLT and conventional therapy combined would result in a greater reduction in licking Visual Analog Score (LVAS) compared to conventional therapy alone. Secondary objectives were to assess change in lesion/ulcer size, thickness and hair growth. ANIMALS: Thirteen dogs with a skin lesion consistent with ALD. METHODS AND MATERIALS: Dogs were randomly assigned to two groups. All dogs received systemic antibiotics and trazodone. The treatment group (TG) received LLLT by laser (130 mW, 2 min) with blue and red light-emitting diodes (LEDs), while the control group (CG) had sham therapy (laser/LEDs off). Treatments were administered three times weekly for two weeks, then twice weekly for two weeks for a total of 10 visits. Descriptive statistics were performed (mean, median); primary and secondary objectives were assessed with nonparametric ANOVA (Kruskal-Wallis test), with significance set at P < 0.05. RESULTS: Thirteen dogs (six CG, seven TG) were enrolled. There were no significant differences in median LVAS, lesion/ulcer size or thickness of the ALD lesion between TG and CG. There was a significantly greater increase (24%) in hair growth in TG (P = 0.0081) compared to CG. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment of ALD requires multimodal therapy. Although combining LLLT with conventional therapy did not result in a significantly greater reduction in LVAS, there was a significant increase in hair growth compared to conventional therapy alone.
Subject(s)
Dermatitis , Dog Diseases , Low-Level Light Therapy , Animals , Dermatitis/therapy , Dermatitis/veterinary , Dog Diseases/radiotherapy , Dogs , Low-Level Light Therapy/veterinary , Treatment OutcomeABSTRACT
BACKGROUND: Staphylococcus pseudintermedius is the most common cause of bacterial skin infections in dogs. Meticillin-resistant infections have become more common and are challenging to treat. Blue light phototherapy may be an option for treating these infections. HYPOTHESIS/OBJECTIVES: The objective of this study was to measure the in vitro bactericidal activity of 465 nm blue light on meticillin-susceptible Staphylococcus pseudintermedius (MSSP) and meticillin-resistant Staphylococcus pseudintermedius (MRSP). We hypothesized that irradiation with blue light would kill MSSP and MRSP in a dose-dependent fashion in vitro as previously reported for meticillin-resistant Staphylococcus aureus (MRSA). METHODS: In six replicate experiments, each strain [MSSP, n = 1; MRSP ST-71 (KM1381) n = 1; and MRSA (BAA-1680) n = 1] were cultivated on semisolid media, irradiated using a 465 nm blue light phototherapeutic device at the cumulative doses of 56.25, 112.5 and 225 J/cm2 and incubated overnight at 35°C. Controls were not irradiated. Colony counts (CC) were performed manually. Descriptive statistics were performed and treatment effects assessed using the Wilcoxon-Mann-Whitney rank-sum test. Bonferroni-corrected rank-sum tests were performed for post hoc analysis when significant differences were identified. RESULTS: There was a significant decrease in CC with blue light irradiation at all doses for MRSA (P = 0.0006) but not for MSSP (P = 0.131) or MRSP (P = 0.589). CONCLUSIONS: Blue light phototherapy significantly reduced CC of MRSA, but not of MSSP or MRSP. The mechanism for the relative photosensitivity of the MRSA isolate is unknown, but is hypothesized to be due to an increased concentration of porphyrin in S. aureus relative to S. pseudintermedius, which would modulate blue light absorption.
